Dostoyevsky77

I'm test-driving an E6750 in my system & with the FSB higher, the memory bandwidth is much greater & I've found that at looser timings (5-5-5-15-2T), tightening tRC also had insignificant performance benefits, whereas with tight timings and lower FSB, there was greater benefit.

**EDIT: Adding some read/write/copy/latency observations at various timings, speeds, two different CPUs and two different 4x1GB combos.

Attached Files

Overclock Notes.txt (2.0 KB, 129 views)

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PhunkedUP

What's the difference between tweaked and OC?

kevg73

tweaked means just trying to get the timings as low as possible for performance. OC is just a reasonable timings that gives you some room to push your cpu OC

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Dostoyevsky77

I wish this were stickied. If I weren't spartan about my sig, I'd have put this thread in there long ago.

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rayd24

I understand most of it WOOOO...its a great description and so much easier to follow than most other write ups! thanks OP.

i found with 4-4-4-12 1T @ 2.2v in everest my Read is 8167MB/s, my write is 2203MB/s, and the latency is 72.8ns.

Is there any way to reduce latency times? more MHz and looser timings? is it very important...I seem to be running better with tighter timings and no OC, from the looks of everest.

Thanks
Ray

Dostoyevsky77

Your RAM is running pretty slow. Typical spread is more like 8000/7000/7000/60ns (read/write/copy/latency).

If you're running a command rate of 1, you must be using a very low clock speed. If you're on a low clock speed, you should consider tightening your timings to 3-3-3-9-1T, and then tightening tRC to 15. If you want to run at higher clock speeds, you must loosen your timings.

I will assume you are running your quad at 344 FSB, so to get a 1:1, you will have set 689 as your RAM clock. 689 is slow, so you'll want timings as tight as possible. If, on the other hand, you wanted to OC the clock speed to - say - 1032 for 3:2, you'd have to open up the timings. That's assuming you have PC2-8500.

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rayd24

Thanks Dostoyevsky! I am gonna try to play around with the timings more tonight and see what results i get. I am actually back at 800MHz clock. My quad is at 3.05GHz (x 7 multiplier) I have PC26400 Originally i had looser timings 5-5-5-15-2T clocked to 1000Mhz but it wasnt stable when the quad was clocked to 3.2Ghz. Oh well.

Dostoyevsky77

Even better. That gives you a FSB of 436, so you can clock your RAM to 871 with fairly loose timings (since this is faster than your PC2-6400s are rated to). That will give you the coveted 1:1. With your fast FSB, this'll give you wide bandwidth and excellent performance. You won't be able to get 1T command rate at that speed, so don't even try. Start with 5-5-5-15-2T and try to get that stable. The mere fact that your computer POSTed at 1000 clock rate on PC2-6400 is worthy of the record books, AFAIC.

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Vinco

Does it matter if you are using 2 different brands of RAM? I have a 1gig kingston stick and 2 512 dual channel kingstons. shouldnt the timings be the same?

onelivestarfish

technically you aren't running in dual channel since you have 3 sticks.
To run in dual channel you would have to have 4 x 512 or 4 x 1 or 2 x 512 or 2 x 1.

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